1. Field of the Invention:
This invention relates to an improved method of packaging semiconductor devices, and in particular to a method of protecting semiconductor dice.
2. Prior Art:
Semiconductor wafers are segmented into a plurality of semiconductor dice, and normally each die is bonded to a lead pattern prior to packaging and testing. That is, a semiconductor die is placed onto a paddle disposed in the center of a lead frame or lead pattern, and contacts on the die are electrically connected to the individual leads of the lead patterns by means of bonding wires. Subsequently, the die with the bonding wires and lead pattern is encapsulated.
Prior to this, the surface of the semiconductor die has remained relatively unprotected during the steps of handling, packaging and testing. The surface of a semiconductor die containing an integrated circuit is sensitive to scratches which may occur during handling of the die. Also, exposure to moisture is deleterious to the surface of the die and function of the semiconductor device.
Lead frames used in the past have included a paddle for mounting the semiconductor die as well as the plurality of electrical leads of the frame disposed for connection to contacts on the die. That is, the paddle is a part of the lead frame structure. This type of lead frame structure makes it difficult to increase the thickness of the paddle without increasing the thickness of the leads. An increased thickness of the paddle could be advantageous to help improve heat dissipation for certain types of integrated or combinations of integrated circuits. Accordingly, the method and structure of the present invention helps overcome this disadvantage by providing protected semiconductor dice which can be mounted on a paddle separate from a lead frame. Also, a die protected in accordance with the method of the present invention can be tested prior to encapsulation.